Rafael Benítez has insisted he will not be swayed by pressure from the Stamford Bridge crowd to select or bring on certain players in matches, as Chelsea's interim first-team manager seeks to improve his side's recent erratic home form to thrust them further clear in third place.

Southampton visit south-west London this evening for a fixture that had originally been scheduled during last month's Club World Cup, with the hosts braced to confront blanket defence yet again. Chelsea may have scored eight against Aston Villa and six against Nordsjaelland under the Spaniard's stewardship, but they have failed to register in any of their other four home games, toothless displays in stark contrast to their away form which has seen 20 goals plundered on six domestic trips.

Both Queens Park Rangers and Swansea City have departed victorious in recent weeks having scored on the break, defeats that have merely added to the poisonous atmosphere at Stamford Bridge. Benítez has been booed by the locals since accepting the reins, but both the chairman, Bruce Buck, and the £50m record signing, Fernando Torres, were subjected to abuse in the Swansea fixture, with the crowd frustrated at the management's apparent reluctance to introduce either Frank Lampard or Demba Ba until the latter stages while the home side chased the game. Benítez later confirmed Ba had been suffering slight discomfort in his knee, with Torres' anaemic display partly explained by a stomach bug.

"You have a word in English: manager," said Benítez. "The manager has to manage and consider everything, and afterwards he has to decide. I talk with my staff, the players, and I have all the feedback and information. Then I make a decision. I consider everything before making a decision. I told you about Fernando's stomach problems last week, and about Ba's slight problem, and I was not making excuses. I was telling you something you didn't know, but still people criticise me for the decisions I made despite the fact Demba Ba had a niggle. I knew Demba could be injured and it would have been a big risk [to play him more], and that was my decision. I will choose the best players to win games. This is always my job, to decide which players are the best for any game."

Both Torres and Ba are available for selection against Southampton, a side Chelsea beat 5-1 at St Mary's in the third round of the FA Cup earlier this month, when the Senegalese striker scored twice on his debut, with John Terry expected to start again on the bench. There is a recognition that Chelsea must be more clinical in front of goal if they are to ease the tension at Stamford Bridge – as they did so spectacularly against Villa – with Benítez anticipating another exercise of attack against defence.

"It is not the atmosphere, but the attitude of the other teams," he said. "In the last two games, they've been very, very deep. We've been pushing and pushing, but we've had to create chances without too much space. Teams are playing here against us with all their players behind the ball: it's something that happens to a top side, so we have to be more clinical, more precise. The players have to take the chances they create.

"There is actually a lot of positivity around [the club]. Look at the stats, the numbers: the team is creating chances and keeping clean sheets. There are a lot of positive signals. My job is to try and concentrate on these positive things – that's the way to go forward."